Due to the accumulated ice in the past thousands of years, the continent has got depressed by about 600m on the average, and it is believed that approximately one third of the sub-glacial land support lies below the sea level. The presence of ice cap gives the continent an average elevation of 2,300m the highest on Earth. If all the ice of Antarctica melts, the continent would be divided into two or more parts and the world sea level would go up by 50 to 60m.
Various expeditions have been able to drill holes in the Ice and extract the Ice samples as old as 1,50,000 years old. Through these ice samples, it has been possible to ascertain the climatological changes and pollution level of the past thousands of years.
The masses of ice flow, slowly from the center of the continent towards its edges, where their movement accelerates to a speed of few hundred meters a year. As the ice sheet reaches the coastal area , it extends into the sea in the form of floating ice shelves , which occupy almost the entire peripheral region of the continent. The three biggest ice shelves are Ross, Ronne & Amery. The ice shelves generally taper towards the sea edge. Inspite of that the seaward edge depth of 400 to 600 m is very common, with maximum being that of Ross Ice Shelf which has a depth of 800 m.
The extended portion of the ice shelves , due to the penetration of sea water as higher temperatures in the coastal regions coupled with swells in the sea water underneath , calves small to large size tabular icebergs which are usually 200 to 300 m thick. These ice bergs can be seen in the region south of 50 degree S. latitude their concentration being very high between 60 to 70 degree S. latitude. Some icebergs as big as 110x75 km have been reported by explorers.
The region connecting the extended portion of the ice shelf and the land ice as known as the Strandcrack region or hinge region. This is the weakest region of the ice shelf , as it has very deep crevasses , seasonal streams , rivers , lakes & an undulating ice surface.